The BSA A7-A10 Forum

Technical (topic titles must be descriptive) => Lucas, Ignition, Charging, Electrical => Topic started by: A10 JWO on 10.02. 2013 14:58

Title: KF2 Plug leads
Post by: A10 JWO on 10.02. 2013 14:58
My old 1954 A10 runs but I have noticed that the odd plug leads are quite old and appear to be copper. some old wise a10 people at the jumble suggest that I replace them with carbon leads that have less resistence. Can the  forum chaps offer me some good advice on these tired old leads and where to get them. I don't intend to scrimp on these important parts.

Regards Colin
Title: Re: KF2 Plug leads
Post by: a10gf on 10.02. 2013 15:02
Quote
replace them with carbon leads that have less resistence
I've always believed it's the copper ones that are right for a magneto, and will have the minimum resistance !??
Title: Re: KF2 Plug leads
Post by: stu.andrews on 10.02. 2013 15:47
Stick to copper, carbon breaks up with age.
Title: Re: KF2 Plug leads
Post by: metalflake11 on 10.02. 2013 16:50
Copper leads all the way. No doubt.
Title: Re: KF2 Plug leads
Post by: Triton Thrasher on 10.02. 2013 17:14
You meet some right idiots at auto jumbles!

The whole point of carbon leads is very high resistance, for suppression of interference with radios, etc. Their resistance can be too high for old magnetos.

If your present HT bits are not failing to spark or giving you shocks in wet weather, they're fine.
Title: Re: KF2 Plug leads
Post by: KenF on 12.02. 2013 20:54
I completely agree with all the other responses, Colin. The 'old wise A10 people' at the jumble got it the wrong way round.

Carbon leads and/or suppressed plug caps and/or resistive sparking plugs make the magneto work harder and suffer more to produce a degraded spark.

We did some experiments a while back. See http://brightsparkmagnetos.com/faqs/FAQs%20about%20magnetos%20generally/Are%20suppressors%20and%20resistor%20sparking%20plugs%20OK%20to%20use%20with%20magnetos.htm (http://brightsparkmagnetos.com/faqs/FAQs%20about%20magnetos%20generally/Are%20suppressors%20and%20resistor%20sparking%20plugs%20OK%20to%20use%20with%20magnetos.htm)

Ken
www.brightsparkmagnetos.com (http://www.brightsparkmagnetos.com)